Not sure if this information will help, but according to "The Book of Dow" there was a Betsey Dow b. Methuen MA 1779 -and family rec. says she m. Peter Peasley. State records (VT I assume, since the family moved from Methuen to Danville VT before 1783) give a marriage of Peter Russell and Betsey Dow on 16 May 1806.
According to the book, Betsey was the daughter ofThomas Dow and Mary Barker. Thomas was the son of Isaac Dow and Martha Hanniford.
The book traces the Dow line to Henry who came to Watertown MA in 1637 - and back a couple more genearations in England..